A flexible display including a flexible display module having a flexible substrate on which a pixel array is formed, a heat radiation sheet portion disposed on a lower surface of the flexible substrate, a display portion and a bending display portion, a cover window disposed on an upper surface of the flexible display module, the cover window including a sidewall portion overlapping the bending display portion of the flexible display module, a middle frame disposed on a rear surface of the flexible display module, the middle frame including a groove portion, a back cover disposed on a rear surface of the middle frame, and a storage space is provided between the groove portion and the back cover.